1. Field of the Invention
This invention relates to improvements in measuring apparatus and method for use in fitting ophthalmic lenses in spectacle frames and has particular reference to applying the ophthalmic measurements directly to frames selected by the patient.
2. Description of the Prior Art
The fitting of lenses to various types of frames selected by patients is ordinarily a tedious, time-consuming and relatively difficult undertaking requiring special skills. It having been generally recognized that the several measurements necessary for optimum ophthalmic glazing are critical, various aids including special scales Pupilometers and frame or lens measuring fixtures have been recommended for obtaining some measurements.
While these lens fitting aids may relieve some of the problems and tediousness in measuring for lens fitting, the accuracy of fitting continues to rely heavily upon the skill and painstakingness of the practitioner together with similar carefulness in proper interpretation and use of the measuring information in the lens finishing shop.
Prior art approaches to applying measurements directly to patient's frames as described in expired U.S. Pat. No. 2,491,312, for example, have required ungainly and overly complicated apparatuses supplying only the heretofore conventional measurements of pupillary distance (PD) from the center of the frame and vertical height of bifocal segment, for example, in each case. These prior art apparatuses additionally require the learning and practice of relatively complicated operating procedures which are individual to each and require a multiplicity of properly sequentially performed steps, e.g. of measuring one lens fitting parameter, neutralizing instrument components and individually measuring another parameter.
Instrument costliness, ungainliness and tediousness of operation have, for the most part, outweighed and discouraged the adoption of these prior art devices in fitting practices in spite of obvious advantages of their applying measurements to the frames.
It is a principal object of the present invention to eliminate conventional measurements, including monocular pupillary distances, yet provide data necessary and sufficient for optimal glazing of ophthalmic frames. The invention applies measurements directly to preselected frames in properly fitted actual positions of use and the measurements taken are directly applicable to the established practice of boxing layout in preparing of ophthalmic lens glazing. Those interested in details of the boxing method may refer to "The Boxing Method of Specifying Eye Size" by by Glen A. Frye, PhD, Journal of the American Optometric Association, February 1959 pages 481-484.